Fetal cardiac function in late-onset intrauterine growth restriction vs small-for-gestational age, as defined by estimated fetal weight, cerebroplacental ratio and uterine artery Doppler

Objective Among late-onset small fetuses, a combination of estimated fetal weight (EFW), cerebroplacental ratio (CPR) and mean uterine artery (UtA) pulsatility index (PI) can predict a subgroup of fetuses with poor perinatal outcome; however, the association of these criteria with fetal cardiac structure and function is unknown. Our aim was to determine the presence and severity of signs indicating cardiac dysfunction in small fetuses, classified as intrauterine growth-restricted (IUGR) or small-for-gestational age (SGA), according to EFW, CPR and UtA-PI. Methods A cohort of 209 late-onset small fetuses that were delivered > 34 weeks of gestation was divided in two categories: SGA (n= 59) if EFW was between the 3rd and 9th centiles with normal CPR and UtA-PI; and IUGR (n= 150) if EFW was < 3rd centile, or < 10th centile with a CPR < 5th centile and/or UtA-PI > 95th centile. The small population was compared with 150 appropriately grown fetuses (controls). Fetal cardiac morphometry and function were assessed by echocardiography using two-dimensional M-mode, conventional and tissue Doppler. Results Compared with controls, both IUGR and SGA fetuses showed larger and more globular hearts (mean left sphericity index +/- SD: controls, 1.8 +/- 0.3; SGA, 1.5 +/- 0.2; and IUGR, 1.6 +/- 0.3; P< 0.01) and showed signs of systolic and diastolic dysfunction, including decreased tricuspid annular plane systolic excursion (mean +/- SD: controls, 8.2 +/- 1.1; SGA, 7.4 +/- 1.2; and IUGR, 6.9 +/- 1.1; P< 0.001) and increased left myocardial performance index (mean +/- SD: controls, 0.45 +/- 0.14; SGA, 0.51 +/- 0.08; and IUGR, 0.57 +/- 0.1; P< 0.001). Conclusions Despite a perinatal outcome comparable to that of normal fetuses, the population of so-defined SGA fetuses showed signs of prenatal cardiac dysfunction. This supports the concept that at least a proportion of them are not 'constitutionally small' and that further research is needed. Copyright (C) 2015 ISUOG. Published by John Wiley & Sons Ltd.